The present invention relates to systems for detecting intruders.
System of these general types are known in the art. They are based on different approaches. It is believed that there is a need to further improve the existing systems in the sense of increasing their accuracy for the purpose of more reliable and earlier detection of an intruder.
Accordingly, it is an object of present invention to provide an improved system of detecting an intruder.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a system which has the steps of providing a sensor which senses a seismic action generated in a ground by an intruder and produces a signal; determining portions of signals from individual steps and making values of the signal with this portion closer to one another; determining a main amplitude threshold; obtaining an enveloping line of initial data of the signal; determining maximum values of amplitudes of the enveloping line and time points corresponding to the maximum amplitudes; determining an average value of time intervals between neighboring maximums of amplitudes and an average square value of the intervals of an average value; making more accurate the average value of time intervals between neighboring maximums of amplitudes of the enveloping line and average squared deviation of the time intervals from an average value, as well as other parameters; and making a decision about a presence of an intrude from the thusly determined parameters.
When the system is designed in accordance with the present invention, it provides a high accuracy of detecting an intruder.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.